Colds and flu are contagious viral respiratory conditions. Coughs and sore throats are common symptoms of colds and flu.
Symptoms tend to be worse with the flu and hit you faster than those of a cold.
Our doctors and their care teams can diagnose your cough, sore throat, or other flu or cold symptoms. They can offer medicines and home treatments to help you feel better.
On this page:
What Are Coughs, Colds, Flu, and Sore Throats?
Colds and flu are both contagious respiratory illnesses caused by different viruses.
Coughs and sore throats are common symptoms of colds and flu. Allergies, strep throat, and other health problems can also cause coughs and sore throats.
The flu often comes on suddenly and is worse than the common cold.
Most common colds are unlikely to cause other health problems.
The flu, if left untreated, can:
- Cause pneumonia.
- Put you in the hospital.
- Even cause death.
Most people get two to three colds each year. The flu is less common, infecting about 8% of people in the U.S. each year.
What causes coughs, colds, and flu?
More than 200 viruses can cause cold symptoms, including a sore throat, cough, runny nose, and headache.
Strains of the influenza virus are what cause the flu.
Other health problems, like allergies or strep throat, can also cause symptoms of a cold.
When someone infected with a cold or flu virus coughs, sneezes, or speaks, they send microscopic virus particles into the air. If you're near that person, you can then breathe in the virus and get sick.
A cold or flu virus can infect you before you get symptoms like a cough or sore throat.
Some people can "carry" the virus and infect others for a short time, even though they never get symptoms themselves. In other words, you can get a cold or flu from someone who doesn't have symptoms.
You can also get a cold or flu by holding hands, kissing, and other forms of close contact.
Coughs, colds, flu, and sore throats risk factors
Certain risk factors can make you more likely to get a cold or flu. These risk factors can also mean you get more severe symptoms.
Cold and flu risk factors include:
- Age — Younger children get more colds each year and are more likely to get the flu, too. Older adults are more likely to become very sick from respiratory viruses, especially the flu.
- A weak immune system — People with weaker immune systems from a health problem or medicine are more prone to getting cold or flu symptoms.
- Stress and poor sleep — You're more likely to get cold symptoms when you're stressed or sleep-deprived. That's because your immune system isn't as able to fight off the virus.
- Exposure — People who are in close quarters with many other people have a higher chance of getting a cold or flu. For instance, you may notice you get cold or flu symptoms after a party or airplane trip.
- Smoking — People who smoke get more colds. Smoking can weaken your immune system, and it also damages the protective membranes in the nose and throat. Their cold symptoms are often more severe and last longer compared to people who don't smoke.
Complications of coughs, colds, flu, and sore throats
Sometimes, the virus that causes the flu or even a common cold can spread to the lungs. This causes viral pneumonia — a lung infection that can be serious as it causes trouble breathing.
Cold and flu viruses can also:
- Make asthma worse.
- Spread to the ears and sinuses, causing ear infections and sinusitis.
- Weaken the immune system, allowing bacteria to take over in the lungs (bacterial pneumonia).
The flu is more dangerous than the common cold. Though rare, the flu can cause swelling in the heart or brain, and impair kidney function.
When should I see a doctor for a cold or flu?
You should see a doctor if you have:
- A fever or cough that goes away but comes back within days or weeks (could be pneumonia).
- Difficulty breathing.
- Fast breathing or fast heart rate.
- Fever that lasts beyond four days.
- Symptoms that don't get better after 10 days.
How can I reduce my risks of getting a cold or the flu?
To reduce your risk of getting colds and flu, you can:
- Avoid people with cold symptoms.
- Get enough sleep and reduce stress.
- Give your body the nutrients it needs to fight viruses. Eat a wide range of fruits, veggies, whole grains, and lean proteins.
- Stop smoking.
- Wear a mask in crowded areas, especially during colder months (October to May) when colds and flu spread much more.
- Wash your hands often.
- Get your yearly flu vaccine to prevent severe flu symptoms and help prevent spreading the flu to other people.
What Are the Symptoms of Colds and Flu?
Colds can last a day to a few weeks.
Symptoms of a cold include:
- Cough.
- Sore throat.
- Runny or stuffy nose.
- Headache.
- Watery eyes.
- Sneezing.
The flu can also last a few days to a few weeks.
Flu symptoms are like cold symptoms, but they come on more quickly and are usually more severe. Plus, the flu causes fever, fatigue, and body aches much more often than colds do.
How Do You Diagnose Colds and Flu?
Your doctor will:
- Ask about your symptoms, including when they started.
- Look at the back of your throat for signs of infection, like swelling and redness. If strep bacteria is the cause of your sore throat, the doctor may see white patches.
- Use a stethoscope to listen as you breathe to check if the infection has spread to your lungs. When people have pneumonia, the lungs make crackling or rumbling sounds.
- Possibly get a nasal swab to diagnose flu.
If your doctor suspects pneumonia, they may order an x-ray to look for fluid in the lungs.
What's causing my cough or sore throat if it's not a cold or flu?
Other possible causes of a cough or sore throat include allergies, strep throat, and tonsillitis.
- Allergies are immune system reactions to allergens, usually harmless substances that the body mistakenly identifies as dangerous. When it happens, the immune system overreacts and triggers symptoms ranging from mild to severe.
- Strep throat is a contagious bacterial infection that causes an extreme sore throat. You may also have a fever and a hard time swallowing. Your doctor can prescribe an antibiotic to kill the bacteria and get rid of your symptoms.
- Tonsillitis is an inflammation of the tonsils caused by a viral or bacterial infection. Telltale signs of tonsillitis include white or yellow spots on the tonsils and voice changes due to swelling of the tonsils.
In rare cases, more serious health issues like cancers and COPD can also cause long-term coughs and sore throats.
To help diagnose these and other issues that can cause coughs and sore throats, your doctor may order tests like:
- A strep throat test.
- Allergy tests.
- Blood tests.
- X-rays.
- CT or MRI scans.
- Laryngoscopy to look at your voice box.
How Do You Treat Coughs, Colds, Flu, and Sore Throats?
Most colds and flu go away on their own without a doctor's care.
If your symptoms are making you feel lousy, our doctors can offer treatments and advice to help relieve them.
People who could get very sick from the flu should see a doctor right away for early antiviral treatment. This can help reduce the risk of having further issues from the flu. Antiviral treatment for flu works best if you start treatment within 48 hours of symptoms starting.
If you have a cold or flu, you can feel better by:
- Getting rest, so your body can work to destroy the virus.
- Staying hydrated with water, juice, or clear broth. This helps your body flush out the virus, and restore fluids you may lose when sweating with a fever.
- Using a spoonful of honey, salt water gargles, or lozenges to soothe a sore throat.
- Using a humidifier, which will make it easier to breathe if you're congested. It will also help if you have a dry, sore throat.
Over-the-counter drugs to treat coughs, sore throats, and other cold and flu symptoms
You can also get the following medicines over the counter:
- Decongestants or antihistamines for a runny or stuffy nose. These come in pill or nasal spray form. If you are using a decongestant nasal spray, they don't work if taken more than three days in a row, so save them for the worst days.
- Pain medicine, like acetaminophen or ibuprofen, for headaches, muscle aches, or fevers.
- Cough suppressants.
Doctors don't advise taking OTC cough medicines for more than a week. Plus, decongestant nasal sprays stop working if you take them more than three days in a row, and can then make symptoms worse.
If your cold or flu symptoms continue after a week without improving, see your doctor for help.
